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Re: Shapes Constraint Language (SHACL) Working Draft of 2017-02-02

From: Irene Polikoff <irene@topquadrant.com>
Date: Wed, 8 Feb 2017 18:31:43 -0500
Cc: "<public-rdf-shapes@w3.org>" <public-rdf-shapes@w3.org>
Message-Id: <AD7D4D72-FC1A-4F01-ABD9-B244F8762EFF@topquadrant.com>
To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Yes, your input has resulted in the clarifying updates in the most recent Editor’s Draft. Thank you.

Personally, I do not see “can be used” as being “somewhat ambiguous”, especially in the context of all other 4 mentions being clearly unambiguous and (optional) labeled in that row, but I am not a native speaker. 


> On Feb 8, 2017, at 6:03 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
> 
> Shapes Constraint Language (SHACL)
> W3C Working Draft 02 February 2017
> 
> SHACL-SPARQL processors MAY pre-bind the variable shapesGraph to provide
> access to the shapes graph.
> 
> Otherwise, for each value node execute the SPARQL query specified by the
> SPARQL-based constraint $sparql pre-binding the variables enumerated in
> 5.3.1 Pre-bound Variables in SPARQL Constraints ($this, $shapesGraph,
> $currentShape).
> 
> $shapesGraph 	Can be used to query the shapes graph as in GRAPH
> $shapesGraph { ... }.
> 
> Not all SHACL-SPARQL processors need to support this variable.
> 
> The SPARQL query executions MUST use the same pre-bound variables as
> enumerated in 5.3.1 Pre-bound Variables in SPARQL Constraints ($this,
> $shapesGraph, $currentShape).
> 
> Two for optional, three for mandatory.
> 
> 
> In Shapes Constraint Language (SHACL), W3C Editor's Draft 08 February 2017:
> 
> SHACL-SPARQL processors MAY pre-bind the variable shapesGraph to provide
> access to the shapes graph.
> 
> Otherwise, for each value node execute the SPARQL query specified by the
> SPARQL-based constraint $sparql pre-binding the variables this and, if
> supported, shapesGraph and currentShape as described in 5.3.1 Pre-bound
> Variables in SPARQL Constraints ($this, $shapesGraph, $currentShape).
> 
> $shapesGraph (Optional) 	Can be used to query the shapes graph as in
> GRAPH $shapesGraph { ... }
> 
> Not all SHACL-SPARQL processors need to support this variable.
> 
> The SPARQL query executions above MUST use the pre-bound variables this and,
> if supported, shapesGraph and currentShape as described in 5.3.1 Pre-bound
> Variables in SPARQL Constraints ($this, $shapesGraph, $currentShape).
> 
> Four for optional, one somewhat ambiguous.
> 
> 
> So the problem definitely existed as of 2 Februrary 2017 and is not quite
> yet eradicated.
> 
> 
> 
> Peter F. Patel-Schneider
> Nuance Communications
> 
> 
> On 02/08/2017 10:22 AM, Irene Polikoff wrote:
>> I originally searched for *$shapesGraph* only. I now see the sentence you are referring to.
>> 
>> Irrespective, I believe the spec currently doesn’t have any tensions. It is consistently clear throughout that the support for this variable is optional and not a requirement for conformance.
>> 
>> Irene
>> 
>>> On Feb 8, 2017, at 12:25 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
>>> 
>>> Both the current editors' draft and the current working draft still include
>>> 
>>> SHACL-SPARQL processors MAY pre-bind the variable shapesGraph to provide
>>> access to the shapes graph.
>>> 
>>> Please try to carefully examine the document before replying.
>>> 
>>> peter
>>> 
>>> 
>>> On 02/07/2017 10:02 PM, Irene Polikoff wrote:
>>>> Peter,
>>>> 
>>>> The word MAY was not used to talk about this variable in the published draft.
>>>> Having said this, I think the tension you are describing may have to do with
>>>> the fact that section 5.3.1 talks about $shapesGraph and $currentShape as
>>>> optional *if supported*, while sections 5.3 and 6.3 that refer to it said that
>>>> these variables MUST be used.
>>>> 
>>>> Please see modified language for sections 5.3 and 6.3 in the latest editor’s
>>>> draft. Does this clarify the topic in your view?
>>>> 
>>>> Regards,
>>>> 
>>>> Irene Polikoff
>>>> 
>>>>> On Feb 7, 2017, at 6:18 PM, Peter F. Patel-Schneider <pfpschneider@gmail.com
>>>>> <mailto:pfpschneider@gmail.com>> wrote:
>>>>> 
>>>>>>> 
>>>>>>> * $shapesGraph
>>>>>>> 
>>>>>>> The status of $shapesGraph is unclear:
>>>>>>> "SPARQL variables using the $ marker represent external values that must be
>>>>>>> pre-bound or substituted in the SPARQL query before execution."
>>>>>>> "SHACL validation engines MAY pre-bind the variable $shapesGraph to provide
>>>>>>> access to the shapes graph.”
>>>>> 
>>>>>> RESPONSE: Please clarify the issue. What is unclear?
>>>>> 
>>>>> The first sentence says that $-marked variables must be pre-bound or
>>>>> substituted.  The second contracts that by using may.  The wording here has
>>>>> changed somewhat, but it is still a tension between the two wordings.
>>>> 
>> 
Received on Wednesday, 8 February 2017 23:32:19 UTC

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